The invention relates to apparatus for preparing a sterile puncturing device for blood vessels in which a non-sterile ultrasound probe can be used, and to a puncturing device of this type.
The ultrasound probe in such a device has a transmitter/receiver system by means of which ultrasound can be irradiated into the body and a signal from the partly reflected beam can be recorded. Due to the Doppler effect, reflection by the flowing blood leads to a frequency shift from which an acoustic and/or optical signal can be obtained. By seeking a maximum for such a signal it is possible to find the point of penetration for the puncturing needle.
Devices of this type are known, for example, from Swiss Patent Specification No. 676 787. The transmitter/receiver system disclosed therein is so constructed that a guide duct for the needle runs through the acoustic resonator. This design is disadvantageous because puncturing must be performed under sterile conditions and because the required gas sterilization of the ultrasound probe is very time-consuming. In a simpler ultrasound probe without an integrated guide duct sterility can be achieved with a sterile covering intended for use once only (see for example EP-A 0 104 618). In these simpler probes, however, the needle cannot run coaxial with the ultrasound beam transmitted.